


Invader Zim X Reader - Cthulhu

by writeyouin



Category: Invader Zim
Genre: F/M, Fun, Halloween, Halloween Costumes, M/M, Reader-Insert
Language: English
Status: Completed
Published: 2019-11-03
Updated: 2019-11-03
Packaged: 2021-01-21 08:20:37
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,098
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21296402
Author URL: https://archiveofourown.org/users/writeyouin/pseuds/writeyouin
Summary: Halloween Request: Reader human SO comes to Zim begging him to help them engineer and build a really elaborate and creepy Halloween costume of some weird and unsettling creature/monster.
Relationships: Zim (Invader Zim)/Reader, Zim (Invader Zim)/You
Comments: 3
Kudos: 52





	Invader Zim X Reader - Cthulhu

“Come on Zim, _please_,” You begged, hands clasped tightly in a ball.

Zim considered your plea, wondering why you weren’t dropping the matter. You had asked for a Halloween costume and he had repeatedly told you that he wasn’t going to waste precious hours of his plotting time making you anything to do with the pit-staining holiday. Usually, when he rejected your incessant human needs, you would shrug and go about your day, totally non-plussed, but this time you just kept _talking._

“No,” He growled, finally getting irritated, which took him a while, considering he’d gotten used to how much of a pain GIR was compared to you.

“I will clean your lab for a month.”

“No.”

“I will make GIR stop pestering you for a while.”

“No.”

“I will find a way to shove Dib into a pig’s mouth until he’s digested.”

“Those creatures eat people? I KNEW IT!”

Your eyes lit up hopefully, “Is that a yes?”

“No.”

“Why not?”

Zim slapped his face, dragging his hand down it exasperatedly. “(Y/N), if I make a costume for you, then I have to make a costume for GIR and that will be far, far too much hassle. ON TOP OF THAT I DON’T WANT TO. _When_ did it become a rule for me to entertain you or any of your other FESTERING BABOON KIND?”

“It became your duty when I found out what you are, didn’t tell anyone, and then you asked _me_ to teach you about human courtship rituals,” You harrumphed, sick of being Zim’s plaything whenever he wanted, whilst receiving nothing in return.

Zim made a series of frustrated noises, pulling at his antenna to relieve the tension. He didn’t know what to do with you when you were like this.

GIR, having heard the majority of the argument from inside a random pile of haggis that had no rightful place in the lab, started laughing hysterically, “Somebody’s in trouble.”

“GIR, DO NOT MOCK ME! HELP ME GET RID OF (Y/N) SO I CAN WORK IN PEACE.”

“IMMA FIX YOU UP,” GIR replied, throwing a book at Zim’s head and ducking back down into his haggis pile.

Zim read the crayon on the front aloud, “The GIR guide to relationships.”

Sticking his lip out in consternation, Zim read on silently, skipping past the pictures of rainbows and flying moose to a page called _What to Do When They’re Angry._

Apparently, he was supposed to ‘_Smooth things over_’ by asking you why this event was important. Although Zim pretended not to care about you, he did very much so, ever since he’d received his first ever compliment from you. Moreover, he loved showing off his human mate to Dib, who also had something of a crush on you; it annoyed the tiny-brained Dib more than anything whenever Zim got close to you.

“On my planet, we have only one holiday,” Zim stated in a superior manner. “The day of the ALMIGHTY TALLEST. That is a day of true importance, unlike this DISGUSTING candy nightmare day. WHAT IS ITS PURPOSE? WHAT SECRETS DOES IT HOLD?”

You knew that was Zim’s long-winded way of asking what the holiday meant to you and you looked to him pleadingly, “I don’t really know how to put it Zim, but imagine if I told you that you couldn’t celebrate your one holiday properly.”

“HERECY!” Zim screeched.

“Exactly. Halloween- Well, it’s a day to be scarier than the things that scare us, among other things.”

“Hmm,” Zim held his hand to his chin thoughtfully.

Stuck in his thoughts, Zim continued making the sound for no less than half an hour, by which time you had got bored and left with GIR to watch TV upstairs; it wasn’t worth interrupting Zim when he got like this, he would only have to start his thought process over again if you did. Finally, Zim had an idea of such evil proportions, the Tallest would have to be impressed.

“COMPUTER! Search the most evil, the most horrifying, the most _abominable _Earth nightmare you can. This Halloween will be the first of a new era, THE ZIM ERA! THE HUMANS SHALL RUE THE DAY-”

“Are you done?” The computer moaned boredly.

Zim held back a choked cry of outrage, if only to look at the research his computer had uncovered. When he read the new document, he grinned, the grin quickly turning into a maniacal laugh that echoed in the lab. Yes, you would have your costume, and it would be horrifying.

* * *

“What is it?” You asked dubiously, staring at the little orb that Zim had just proudly pressed into your hand.

“Your costume,” Zim stated as if it was the most obvious thing in the world.

“…It’s just a ball.”

“NO! This is a marvel of Irken technology. When you go outside, crush the ball in your fist and billions of my nanobots will form an exoskeleton around your body, creating THE BEST HALLOWEEN COSTUME IN THE WORLD!”

Your eyes lit up animatedly, “Really? That’s so cool.”

“Indeed, it is freezing on the scale of human appreciation. Now, what are you waiting for? Let’s go.”

Zim dragged you outside to the sidewalk, where he gave you an encouraging nod to crush the ball. You couldn’t wait to see what kind of costume he’d designed for you. The second you crushed the tiny orb, you felt the nanobots, cocooning you safely inside their costume. A helmet appeared first, letting you watch as your new armour was built around you. You watched as the bots interlinked, making you taller and broader. You could just see the tentacles that grew on your helmet, a slimy texture coating them.

A lady with two children further down the street started screaming, yet you could do nothing as you grew even taller, towering over the surrounding buildings.

“UH, ZIM!?” You cried out, the costume transforming your voice into a monstrous roar. “ZIM, WHAT’S HAPPENING?”

“YOU WANTED TO BE A MONSTER DID YOU NOT?” Zim cackled. “THEN BE A MONSTER!”

You had no control over your limbs as you started destroying the buildings around you. A timer appeared on a computer screen next to you. ‘_Time remaining as Cthulhu, twelve hours and counting._’

“ZIM, WHEN I STOP DESTROYING THIS CITY, YOU AND I ARE GOING TO HAVE A SERIOUS TALK ABOUT CONSENT!” You bellowed, crushing your neighbours house with a desperate apology.

Zim only laughed harder, chasing after you to make sure Dib could not get in the way of his master plan; you were right, Halloween was a good holiday.


End file.
